With development of the panel display industry, requirement on the display panel is getting higher and higher, wherein requirement on mobility of a thin film transistor in the panel is getting higher. Currently, an existing thin film transistor (TFT) is usually a amorphous silicon thin film transistor, an active layer of which is amorphous silicon material. The amorphous silicon thin film transistor has a low electron mobility of 0.1-1 cm2V−1s−1, which cannot meet the demand of technology development. Therefore, low temperature poly silicon (LTPS) thin film transistors and oxide thin film transistors are researched and developed.
The LTPS thin film transistor is a thin film transistor with an active layer made of low temperature poly silicon material. The low temperature poly silicon is obtained by converting amorphous silicon into poly silicon at a low temperature. The LTPS thin film transistor has a high carrier mobility up to about 100-500 cm2V−1s−1, however, its uniformity is poor and thus an insurmountable problem occurs when the thin film transistor is applied to a big-size panel. The oxide thin film transistor is a thin film transistor with an active layer made of an oxide semiconductor material, which ensures a good big-size uniformity while sacrificing carrier mobility to some extent, and at present, under premise of ensuring a good uniformity, the carrier mobility of the oxide thin film transistor can reach up to 10 cm2V−s−1. However, the carrier mobility of the oxide thin film transistor can not meet the development of the panel display technology any longer. Therefore, the carrier mobility of current thin film transistors needs to be further improved under good uniformity.